3

我有一张高分表scores: (id int, deviceid int, value int, board int)。我想显示特定玩家的位置。目前我正在这样做（在 PHP 中）：

我选择玩家有分数的所有棋盘和分数本身：

select board, min(value) as value
from scores
where deviceid = 1234
group by board

然后对于每一行 ($board,$value) 我选择：

select count(id) from scores
where board = $board and value < $value

通过选择分数小于指定值的特定板的行数，我得到玩家的位置（第一个玩家将获得位置 0，因此显示时它将增加 1）

我知道这是非常低效的，所以我正在寻找一种更快的方法。它可以在带有游标的存储过程中完成，但是对于 100 个板，我最多需要进行 1+100 次选择。

简而言之，我想在伪 sql 中做这样的事情：

select board, min(value) as val,
       count(id) from _this_group_ where value < val
from scores
where deviceid = 1234
group by board
4

2 回答 2

2 
SELECT scores.board, count(1) AS position
FROM scores
JOIN
  (SELECT board, MIN(value) AS value
   FROM scores
   WHERE deviceid = 1234
   GROUP BY board
  ) player_scores
ON scores.board = player_scores.board
WHERE scores.value < player_scores.value
GROUP BY scores.board
于 2012-07-31T11:50:00.680 回答
0

您可以尝试以下方法：

SELECT a.board, b.val COUNT(1) AS cnt
FROM scores a
    INNER JOIN(
        SELECT board, MIN(value) as val
        FROM scores
        WHERE deviceid = 1234
        GROUP BY board
    ) b
     ON a.board = b.board
    AND a.value < b.val
WHERE a.deviceid = 1234
GROUP BY a.board;

或者

SELECT a.board, MIN(a.value) as val,
       (SELECT COUNT(1)
        FROM scores b
        WHERE b.board = a.board AND
        b.value < MIN(a.value)) AS cnt
FROM scores a
WHERE a.deviceid = 1234;
于 2012-07-31T11:32:05.133 回答